KUALA LUMPUR, Malaysia—The son of Kim Jong Nam, the estranged half brother of North Korea’s ruler who was killed in Malaysia three weeks ago, has appeared in an online video posted by a group that says it rescued his family with the assistance of four governments.

Speaking English, he identifies himself as Kim Han Sol, shows his redacted passport, and says he is speaking a few days after the Feb. 13 killing and is safely with his mother and sister. The YouTube video is dated March 7.